• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 212
  • 69
  • 42
  • 33
  • 23
  • 13
  • 4
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 448
  • 448
  • 89
  • 88
  • 67
  • 63
  • 63
  • 46
  • 43
  • 39
  • 35
  • 31
  • 30
  • 29
  • 28
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

A Bluetooth based intra-satellite communication system

Hagen, Christoph January 2017 (has links)
This thesis presents a wireless communication system for intra-satellite communication based on Bluetooth Low Energy technology, which can have many benefits regarding the design and operation of satellites. The proposed design based on the nRF53832 chip from Nordic Semiconductor is described, followed by the results of several tests regarding the most important design criteria for its application in small satellites. The tested aspects include the power consumption of the wireless module in different operation modes, which is sufficiently low for the application even in small satellites. Signal strength measurements for various output power settings and obstacles show that reliable communication is possible in a satellite mockup. No packet error was detected, and latencies of less than 30 ms combined with achievable data rates between 200 and 700 kbps should be sufficient for most CubeSat satellites. Additionally, details are given to successfully integrate the chip with existing satellite subsystems. A code library is provided to simplify the communication between the modules, and a concept of a redundant system is established to increase the reliability for critical satellite subsystems. The overall assessment of the technology suggests that the presented system is suitable for in-orbit deployment with the Aalto-3 satellite (currently being developed at Aalto University), which will provide further validation of the technology.
152

TiO2(110) surface structure

Busayaporn, Wutthikrai January 2010 (has links)
In this thesis three studies of the geometric structure of the (110) surface of single crystal rutile TiO2 are presented. Firstly, quantitative low energy electron diffraction (LEED-IV) data acquired from TiO2(110)(1x1) are reanalysed to confirm the integrity of the previously reported optimized geometries by performing structural optimisation as a function of depth into the selvedge. The second study addresses the geometry of the x-linked (1x2) reconstruction of the same surface. Again, LEED-IV data are analysed to quantitatively determine the surface structure. Part of this effort involved substantial development of the code (SATLEED) employed for simulating the experimental data, to allow simultaneous optimisation of more than one surface termination. In contrast to recent scanning probe work, the analysis indicates that the surface consists of two differently relaxed Ti2O3 added rows. The last study concerns ab initio calculations of the structure of benzoate on TiO2(110)(1x1). Of particular interest is the impact of surface coverage on the orientation of the benzene ring. It is predicted that the benzene ring twists and tilts away from high symmetry with increasing coverage due to adsorbate-adsorbate interactions. No evidence is found to support the formation of benzoate dimers or trimers, as was concluded in earlier experimental work.
153

Nízkoenergetické bydlení a průzkum trhu / Low -- energy houses and market research

Martinů, Iva January 2008 (has links)
This diplomate thesis will have two parts, theoretical and practical. The first part of this diplomate thesis contains short analyse of consumption and prices of energy which we need on heating. In the next part will be described ecological (low -- energy) housing in general, which would have protect the environment. The second part will be about charkteristics and criterias, fundamental elements of low -- energy housing and main aims of low -- energy housing. The following part of this thesis will contain information about energy balance of houses, concretely which heat gains and losses exit. For construction of these buildings is very important building -- energy conception of building and technical arrangement of houses. The last part will be about the contemporary trend of ecological building -- up in the Czech Republic. This thesis will continel in practical part, on research of the Czech market. Concretely market research from the look of consumers, what is their demand, what lead them to build low -- energy houses, who is the typical consumer, etc. Further from the look of designer and building societies. The method will be questionnaire inqeury. Purpose of this diplomate thesis will be to valorize the situation about low -- energy housing on the Czech market.
154

Exploration Of Energy And Area Efficient Techniques For Coarse-grained Reconfigurable Fabrics

Yadav, Anil 12 1900 (has links)
Coarse-grained fabrics are comprised of multi-bit configurable logic blocks and configurable interconnect. This work is focused on area and energy optimization techniques for coarse-grained reconfigurable fabric architectures. In this work, a variety of design techniques have been explored to improve the utilization of computational resources and increase energy savings. This includes splitting, folding, multi-level vertical interconnect. In addition to this, I have also studied fully connected homogeneous and heterogeneous architectures, and 3D architecture. I have also examined some of the hybrid strategies of computation unit’s arrangements. In order to perform energy and area analysis, I selected a set of signal and image processing benchmarks from MediaBench suite. I implemented various fabric architectures on 90nm ASIC process from Synopsys. Results show area improvement with energy savings as compared to baseline architecture.
155

Wearable Devices for Non-Invasive Cardiorespiratory Monitoring

January 2020 (has links)
abstract: Wearable technology has brought in a rapid shift in the areas of healthcare and lifestyle management. The recent development and usage of wearable devices like smart watches has created significant impact in areas like fitness management, exercise tracking, sleep quality assessment and early diagnosis of diseases like asthma, sleep apnea etc. This thesis is dedicated to the development of wearable systems and algorithms to fulfill unmet needs in the area of cardiorespiratory monitoring. First, a pneumotach based flow sensing technique has been developed and integrated into a face mask for respiratory profile tracking. Algorithms have been developed to convert the pressure profile into respiratory flow rate profile. Gyroscope-based correction is used to remove motion artifacts that arise from daily activities. By using Principal Component Analysis, the follow-up work established a unique respiratory signature for each subject based on the flow profile and lung parameters computed using the wearable mask system. Next, wristwatch devices to track transcutaneous gases like oxygen (TcO2) and carbon dioxide (TcCO2), and oximetry (SpO2) have been developed. Two chemical sensing approaches have been explored. In the first approach, miniaturized low-cost commercial sensors have been integrated into the wristwatch for transcutaneous gas sensing. In the second approach, CMOS camera-based colorimetric sensors are integrated into the wristwatch, where a part of camera frame is used for photoplethysmography while the remaining part tracks the optical signal from colorimetric sensors. Finally, the wireless connectivity using Bluetooth Low Energy (BLE) in wearable systems has been explored and a data transmission protocol between wearables and host for reliable transfer has been developed. To improve the transmission reliability, the host is designed to use queue-based re-request routine to notify the wearable device of the missing packets that should be re-transmitted. This approach avoids the issue of host dependent packet losses and ensures that all the necessary information is received. The works in this thesis have provided technical solutions to address challenges in wearable technologies, ranging from chemical sensing, flow sensing, data analysis, to wireless data transmission. These works have demonstrated transformation of traditional bench-top medical equipment into non-invasive, unobtrusive, ergonomic & stand-alone healthcare devices. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2020
156

軽い核におけるlow-energy dipole励起モードのクラスター構造による理解

四方, 悠貴 23 March 2021 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第22998号 / 理博第4675号 / 新制||理||1670(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)准教授 金田 佳子, 教授 萩野 浩一, 教授 田中 貴浩 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
157

Ekonomické posouzení výstavby pasivních a aktivních domů / Economic Assessment of the Construction of Passive and Active Houses

Ondra, Filip January 2019 (has links)
This diploma thesis examines the economics of use of technologies linked with low-energy, passive, and active house construction which is presently very often a topic of interest. The goal of the thesis is to evaluate economic effectivity of additional investment into construction materials leading to reduction of heating requirements of the evaluated family house. Furthermore, economics of the use of advanced technologies of ventilation, different heat sources and photovoltaic power plant are assessed. The result is a complex evaluation of different alternatives of the house which makes this thesis helpful in answering the question whether these additional investments will pay off.
158

Hloubkové profilování multivrstev metodou LEIS / Depth profiling of multilayers by LEIS

Strapko, Tomáš January 2019 (has links)
Diplomová práce se zabývá vytvořením modelu, který by umožnil lepší interpretaci hloubkových profilů měřených metodou LEIS. Obtížnost interpretace těchto profilů je dána vysokým podílem vícenásobně odražených projektilů v meřených spektrech. Tyto projektily nepřináší užitečnou informaci z dané hloubky. Naproti tomu jednonásobně odražené projektily nesou přesnější informaci o složení a tloušťce vrstev. V této práci vytvořený model se snaží určit příspěvek jednonásobně odražených částic k celkovému tvaru spektra a na základě něj i hloubkový profil vzorku.
159

Products of low energy electron impact induced excited state reactions of carbon monoxide and of nitric oxide on a gold surface

St. Denis, Michael Joseph 01 January 1989 (has links)
The threshold potentials were determined for the excitation energy necessary for low energy electrons to induce chemical reactions of carbon monoxide, and of nitric oxide adsorbed on a gold surface. The reactions were studied as a function of temperature (100 °C to 200 °C) and pressure (1.83 x 10-5 to 6.40 x 10-4 torr). The electron source was a thorium oxide coated iridium filament which was heated by a current between 1A and 3A to keep thermal distribution of the electrons to less than 0.4 ev. The reaction surface was a polycrystalline evaporated film prepared by subliming gold onto a stainless steel mesh support. Mass analysis was done by quadrupole mass spectrometry in a flow system. The general results of the research is that a technique has been developed to study the products of reactions of excited state atoms or molecules on metal surfaces. The electron-impact excitation method is an alternative to photochemical and other methods.
160

Systém lokalizace uvnitř budov / Indoor positioning system

Celeng, Michal January 2016 (has links)
The work deals with the issue of indoor positiong system in the enviroment of the Android operating system, based on the efficient standard Bluetooth Low Energy, with conjunction of bluetooth beacons. The outcome of master‘s thesis is system topology, description of its components, standards needed for his creation and finally construction of the system.

Page generated in 0.0594 seconds